mecsbasic.c

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/*
This file is part of BitPunch
Copyright (C) 2015 Frantisek Uhrecky <frantisek.uhrecky[what here]gmail.com>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "mecsbasic.h"

#include <bitpunch/math/gf2.h>
#include <bitpunch/debugio.h>

#ifdef BPU_CONF_ENCRYPTION
int BPU_mecsBasicEncrypt(BPU_T_GF2_Vector *out, const BPU_T_GF2_Vector *in, const BPU_T_Mecs_Ctx *ctx) {
        int rc;
        BPU_T_GF2_Vector *e = ctx->code_ctx->e;
        BPU_gf2VecNull(out);

        // test the size of message and g_m
        if (in->len != ctx->code_ctx->msg_len) {
                BPU_printError("message length has to be of length %d", ctx->code_ctx->msg_len);

                return -1;
        }

        rc = ctx->code_ctx->_encode(out, in, ctx->code_ctx);
        if (rc) {
                BPU_printError("can not encode");
                return rc;
        }

        // generate random error vector e
        rc += BPU_gf2VecRand(e, ctx->code_ctx->t);
        if (rc) {
                BPU_printError("can not init rand vector");
                return rc;
        }

        // z' XOR e
        rc = BPU_gf2VecXor(out, e);
        if (rc) {
                BPU_printError("can not add error vector");
                return rc;
        }
        return rc;
}
#endif

#ifdef BPU_CONF_DECRYPTION
int BPU_mecsBasicDecrypt(BPU_T_GF2_Vector *out, const BPU_T_GF2_Vector *in, const BPU_T_Mecs_Ctx *ctx) {
        int rc = 0;
    BPU_T_GF2_Vector *temp;

        BPU_gf2VecMalloc(&temp, in->len);
    BPU_gf2VecCopy(temp, in);

    rc = ctx->code_ctx->_decode(out, temp, ctx->code_ctx);

    BPU_gf2VecFree(&temp);

        return rc;
}
#endif